For Tarlov Cyst Patients
Patients who are coming to Dr. Long for a Tarlov Cyst should review the information below to better understand the history and diagnosis of Tarlov Cysts as well as the following information about patient visits.
About Symptomatic Tarlov Cysts
Tarlov described the sacral perineural cyst which bears his name in the 1930’s. By 1948 he had collected a number of examples of these cysts which were symptomatic. Some were his own patients and some were reported in the medical literature. He established that these cysts were sometimes symptomatic and occasionally required surgery. At that time, the only imaging studies available were plain x-rays and myelograpy. The cysts were seen because they eroded the bone of the sacrum and could mimic tumors. Most were explored with preoperative diagnosis of a benign tumor. The fact that these cysts were sometimes symptomatic was well accepted.
With the advent of MRI, it was discovered that small cysts were quite common. While no definitive epidemiological studies have been done, the frequency with which the cysts were seen in individuals without complaints gave rise to belief that cysts were always asymptomatic. Over the past 20 years or so, a mythology has grown up that all sacral cysts are Tarlov cysts and are never the cause of symptoms. There is little question that many small cysts occur as normal anatomical variants and do not cause symptoms. However, it has been apparent for half a century that Tarlov cysts are sometimes symptomatic, and the larger they are the more likely they are the cause of symptoms. However, the majority of practicing physicians today have been taught and believe that these cysts are not symptomatic. Radiologists often make that gratuitous comment when describing the cysts, even when they may have little information concerning the patient’s actual symptomatology.
In an effort to understand these cysts and their clinical consequences, about 2003-2004 we began a systematic investigation of the importance of these cysts in causing clinical symptoms related to the spine. These conclusions are based upon our current experience with about 300 patients, 180 aspirations and 70+ surgeries.
We have identified several groups of patients whom we believe have different kinds of cysts and different clinical problems.
The first group of these patients have what appear to be cysts described by Tarlov. These are the majority of patients. Most have one or more large cysts involving sacral nerve roots. The cysts may be on one side or both. Multiple cysts are common. The symptomatic cysts are usually large and typical symptom-causing cyst is 1.5-2 cm. We only have three patients in whom cysts of 1 cm or less may be causing symptoms. Smaller cysts have not been proven definitely to produce symptoms. Three typical clinical syndromes have been identified. Most patient have local pain in the region of the cysts associated with sciatic leg pain, and pain in the pelvic area. Leg weakness, changes in leg sensation, and changes in sensation in the perineum (pelvis) are common. Complaints of bowel, bladder, and sexual dysfunction are common. The second group of patients has local sacral (tailbone) pain, and pain in the pelvis or lower abdomen, typically associated with more significant bowel and sexual dysfunction, but no leg pain. Sensory changes in the perineum (pelvis) are common. The third smallest group of patients has only bowel, bladder, and sex function changes without pain. Symptoms and signs vary with the nerve roots involved in all groups. These same complaints can have many other causes, however.
Another group of patients suffer from dural ectasia or enlargement of normal dura. The typical patient has a disease known to affect connective tissue such as Marfan’s syndrome or Ehlers-Danlos syndrome. Victor McKusick, father of genetic medicine, was the first to make this association in a study done at Johns Hopkins. The dural sac is abnormally large and expanded around nerve roots to form large cysts. Often these cysts go through the sacrum into the pelvis. The majority of patients have been women. The pelvic cystic masses can be huge. The connections with the normal subarachnoid space are very large. These are not true Tarlov cysts, though they are often given this name by radiologists in reports. They result from the weakness of connective tissues which most of these patients suffer.
Another group of patients, who are mostly male, has large midline cysts involving all of sacral nerve roots. These are sometimes associated with what is called a tethered cord syndrome in which the spinal cord comes far lower in the spinal sac than is normally found. These patients often have back and leg pain, pelvic pain, and significant difficulties with bowel, bladder, and sex function. Leg weakness is also common. We believe these are a different developmental abnormality and we believe they should be described as meningoceles. These are not simple Tarlov cysts.
Multiple Spinal Cysts
There is a fourth group of patients which has the most rare manifestation of all. These patients have Tarlov cysts which are not isolated to the sacrum. These are patients who have multiple cysts occurring up and down the spine on many different nerve roots. The usual presenting symptom is pain, which is clearly in the distribution of one or some of the involved nerve roots. When any of these are symptomatic is often difficult to determine.
At present, it is our belief that some patients can be offered treatment when pain is severe and complaints are related to specific nerve roots which are those expected from the location of the cysts, and/or loss of appropriate neurological function. An asymptomatic cyst is not an indication for treatment in our opinion currently. It is also important to determine if there are any other abnormalities in the spine which could explain the complaints. The symptoms which come from the Tarlov cysts may be difficult to distinguish from symptoms generated by other spinal diseases which are much more common. There are no tests which will tell us specifically when symptoms are coming from one or more cysts. Therefore, other spinal and pelvic problems should be investigated and treated as indicated. The decision for treatment of any cyst generally depends upon the severity of symptoms and any associated loss of function. Unless symptoms and signs are severe, we do not recommend treatment of any of the sacral cysts. Symptomatic management is always preferable when symptoms are not severe. Since the natural, untreated history is unknown, we do suggest reevaluation of the cyst(s) by MRI at intervals of 1-2 years, until more is known about their behavior.
There are currently two methods of treatment which we have available. The first is aspiration of the cyst with an injection attempt to obliterate the communications which allow spinal fluid to enter the cyst. The theory is that when cyst is filled with a material (either fat or fibrin sealant) that does not transmit spinal fluid pressure on to the nerve, symptoms should improve. The other way to accomplish the same thing is with direct surgery. These operations have been done for over 60 years. The cyst is usually filled with fat in some form, and with other kinds of tissue sealants as well. If you are a candidate for aspiration, that will be described at the time you are seen in the clinic and will be discussed again with you by the radiologist who will perform the procedure just before the permit is obtained.
Some have employed repeated aspirations of the cysts to try to achieve lasting relief, and some have injected a potent anti-inflammatory medication called a steroid into these cysts. We have no experience with either technique or with the injection of any other materials other than fibrin sealant.
Most of the true Tarlov cysts can be treated by aspiration. The deciding factors are several. If the cyst does not have large communication with the subarachnoid space, then it is reasonable to treat it by injection. When the communication is large, surgery is required to obliterate it. The bone must be thin enough to allow needle placement for aspiration.
The large dural ectasias are not treatable except by direct surgery. Shunting has been used by others to reduce the pressure on the dura in these patients, but we have not seen any convincing reports of outcomes as yet.
The large midline meningoceles can sometimes be treated by aspiration. This is dependent upon the size of the connection with the subarachnoid space and the need to untether an abnormal spinal cord. Most require surgery when treatment is needed.
We have not yet attempted aspiration of many of the unusual cysts which occur in multiple other areas of the spine.
Indications for treatment are still being investigated. Use of the fibrin product is off-label in the operating room and for these injections. The drug has been used to stop spinal fluid leak in the operating room for many years.
The aspiration is done on an outpatient basis with sedation but without general anesthesia. The entire procedure typically takes about one hour. It is performed in the CT machine. Our two-year outcomes are about 65% of patients who indicate they are either cured to substantially better. Obviously since the study has only been in progress for a little over 3 years, we do not know what the eventual outcomes will be. Another 20% are somewhat improved, but not to the point they are satisfied with treatment, and about 15% have just failed completely. Remember this is a new technique and is still being investigated. Injection of the sealant is an off-label use. No other center does this to our knowledge. We are likely to change this information as we gather more data. This material is our best summary of the data now. It may change with more study.
The results of surgery are a little better. 75% of patients have achieved lasting relief. The complete failure rate is only about 5% but there remain some 20% of patients who may be better but are not completely satisfied with treatment outcome. These are major procedures and require general anesthetic and hospitalization.
Complications of Aspiration and Surgery
There have been very few complications or problems with the aspiration technique in our series. In three patients we found that refilling of the cyst was faster than anticipated and we did not believe it was safe to carry out the procedure. One patient developed an allergic reaction which could have been to the injected sealant or to the sedating pain medication. That event required overnight hospitalization. Two patients report they have been permanently worsened by aspiration. Four patients have had increased pain after the procedure which lasted from two days to three weeks. All of those patients are now significantly improved. No lasting spinal leaks have occurred, but two patients required the injection of a blood patch for headache. The major complication of aspiration is that some of the cysts eventually refill and need more treatment. We do not know an exact number because this is an ongoing evaluation which will take several years to be certain about long term outcome. No nerve injuries have occurred. There have been no infections. There are at least 2 reports from other institutions of severe reactions to commercial fibrin glue injected into these cysts or used elsewhere in the body. Whether it is the fibrin injected into these cysts or some contaminant is uncertain. Severe pain, loss of neurological function (paralysis), and even mental changes occurred. The cause is unknown but allergic reaction to glue is suspected. The material is used daily in the OR in many patients throughout the world, so the risk is very low, but you need to know about it because it is so serious. You also must remember this is an off-label use of the fibrin product as is its common use in the neurosurgery operating room to seal spinal fluid leaks.
The major complication of surgery has been spinal fluid leak into the surgical site, which required either another operation or a fibrin sealant injection. In the entire surgical series, the frequency of this complication is about 9%. However, a leak is much more likely to occur in the groups of patients with connective tissue diseases and in those patients with the large spinal fluid connections between the spinal sac and the cyst. Because of this complication we are now developing a new protocol for evaluation of the patients with either the connective tissue disease or a large spinal connection defect to be filled. This is such an important topic that if there is any question about the size of the potential connection between a cyst and a spinal canal, we may recommend a special study called a CT myelogram. You will be told about this after we have reviewed films to determine if the study is necessary.
There has been one superficial infection in the surgical series and none in the aspiration series. One person developed meningitis after surgery and this was successfully treated with antibiotics. No nerve injuries have occured.
We currently believe it is reasonable to offer aspiration as the first step in treatment for patients in whom this is possible. The majority of patients with true Tarlov cysts can be treated this way. Our 5 year results are favorable but long term results are unknown. Other cysts cannot be aspirated in our experience. When aspiration fails or is not feasible, surgical repair is possible if symptoms are severe.
Evaluation and treatment of patients with these Tarlov cysts and the related sacral cystic abnormalities which occur in the same area is an evolving process. Our care may change as we learn more about the results of current management, but this summary presents our current data for the care of patients with sacral cysts. Some surgeons will not treat patients who have had aspirations. You should consider this in choosing therapy.